Look inside Don Draper's glass. Aside from the industrial level of booze, look at the ice. The 1in cubes are made by an ice-obsessive named Michel who provides bespoke ice for some of Los Angeles's fanciest bars. And its fanciest TV show.

Mad Men's prop master Ellen Freund employs an army of experts across the US to supply props for the Sterling Cooper Draper Pryce offices."I have a guy in Texas called George [Fox] and he's obsessed," she tells me, "not with fancy pens – but with ballpoints. He knows exactly which year and month each pen came out. When I said I wanted to use a [Papermate] Flair he said: 'Uh-uh, 1966!'"

Originally a prop master on films including My Own Private Idaho and Night at the Museum, Freund joined Mad Men in series three.

Meeting the demands of the show's perfectionist creator Matthew Weiner and its sharp-eyed fans can be tricky. "You have a two-day period to find the perfect item that lives in his brain from 1965," says Freund, who spends her weekends scouring garage sales for objects such as jam jars that have been storing screws since the mid-60s. It's these non-collectible bits that are the hardest to find.

The new series sees Draper's new firm take up residence in Manhattan's Time-Life Building. Nearly half a decade on from when we originally met the team at Sterling Cooper, the set design is strikingly more like the 1960s we imagine. Having flogged the old gear on eBay for charity (Lane Pryce's desk lamp? Yours for $740!) a new set gave Freund and production designer Dan Bishop the chance to start again.

"A couple of items, such as someone's bar set, may have stayed," she explains. "And Cooper kept his tea set. But mostly we went all-new, which was fun, to choose new dishware or to just redesign the office."

The 21st-century vogue for 60s design doesn't necessarily make things easier to acquire, though. "It's easier and harder. Collectible means it's more expensive and our budgets are not that big. [It also means that] if we only use things that you see everywhere, it's not that interesting. Part of our job is to surprise you with something that you really haven't seen since your childhood and that's the brown waxed-paper bag around a sandwich or a particular pencil sharpener."

Things can sometimes go wrong – a 1961 Marcels record that appears in episode two sent US vinyl aficionados into a flurry when they spotted that it was on modern reissue label Eric. The crew takes inaccuracies seriously ("Matt would be the first to come over and say 'on this blog . . .'") but sometimes – as with series one's non-period typewriters – items are chosen for their looks rather than their accuracy. Product placement helps – Heineken is thought to have paid to provide the original bottles of beer used in an episode in series two where Betty feels tricked into buying them. And, in this series, Budweiser delved into its archive to provide some cans – Freund drained the 50-year-old beer and replaced it with water so the actors could drink from them.

Convincing viewers that Don and his colleagues aren't actually guzzling back booze might be the hardest sell of all.